1. Field of the Invention
The present invention pertains to patient interface devices structured to deliver a flow of breathing gas to a patient, and, in particular, to a sealing device to apply pressure to a selected area of a cushion member of a patient interface device to resolve a leak along the patient sealing portion of the patient interface devices.
2. Description of the Related Art
There are numerous situations where it is necessary or desirable to deliver a flow of breathing gas non-invasively to the airway of a patient, i.e., without intubating the patient or surgically inserting a tracheal tube in their esophagus. For example, it is known to ventilate a patient using a technique known as non-invasive ventilation (NIV). It is also known to deliver continuous positive airway pressure (CPAP) or variable airway pressure, which varies with the patient's respiratory cycle, to treat a medical disorder, such as sleep apnea syndrome, in particular, obstructive sleep apnea (OSA), chronic obstructive pulmonary disease (COPD), or congestive heart failure (CHF).
Non-invasive ventilation and pressure support therapies involve the placement of a patient interface device, which is typically a nasal or nasal/oral mask, on the face of a patient to interface the ventilator or pressure support system with the airway of the patient so that a flow of breathing gas can be delivered from the pressure/flow generating device to the airway of the patient.
Typically, patient interface devices include a mask shell or frame having a cushion member attached to the shell that contacts the face of the patient. The mask shell and cushion member are typically held in place by a headgear that wraps around the head of the patient. The mask and headgear form the patient interface assembly. A typical headgear includes flexible, adjustable straps that extend from the mask to attach the mask to the patient.
Because such masks are typically worn for an extended period of time, a variety of concerns must be taken into consideration. For example, in providing CPAP to treat OSA, the patient normally wears the patient interface device all night long while he or she sleeps. One concern in such a situation is that the patient interface device is as comfortable as possible, otherwise the patient may avoid wearing the interface device, defeating the purpose of the prescribed pressure support therapy. It is also important that the interface device provide a tight enough seal against a patient's face without discomfort. A problem arises in that, in order for the mask to maintain a seal without any undue gas leaks around the periphery of the mask, the mask must be compressed against the patient's face. Conventional CPAP masks that seal by compression commonly cause uncomfortable pressure points and do not adjust well to different anatomical facial features. The conventional concept of a compression seal is to generally displace tissues on the patient's face in order to achieve a uniform seal. Tissue displacement results in pressure points, skin markings (i.e., red marks), indentations, and overall prolonged discomfort. Conventional seals also commonly distort outward upon compressing and in doing so tend to pull or push on portions of a patient's face in a manner which is uncomfortable. Such distortions can also lead to unwanted leaks.